Thermosetting resin and prepreg and laminate using the same

Abstract

A thermosetting resin composition comprising a special poly(p-hydroxystyrene) derivative resin and a radical polymerization initiator, and if necessary an epoxy modified polybutadiene, can provide prepregs and laminates having a low dielectric constant, a shorter signalling delay time, good heat resistance and flame retardancy and thus being suitable for producing multilayer printed circuit boards.

What is claimed is: 
     
       1. A multilayer printed circuit board comprising a plurality of insulating layers and a plurality of circuit conductor layers, said insulating layers and said circuit conductor layers being laminated and bonded alternately, said insulating layers being obtained by impregnating a sheet-like base material with a varnish containing a solvent and a thermosetting resin composition comprising a poly(p-hydroxystyrene) derivative resin represented by the formula: ##STR7## wherein A is an alkyl group; X is a halogen group; R is an alkylene or alkenoyl group having 2 to 4 carbon atoms; p is an integer of 1 to 4; q is zero or an integer of 1 to 3; and n is an integer of 1 to 100, a radical polymerization initiator and an epoxy modified polybutadiene represented by the formula: ##STR8## wherein Y is an epoxy resin; and m is an integer of 4 to 100, in an amount of 20 to 80% by weight, followed by removal of the solvent by drying. 
     
     
       2. A multilayer printed circuit board comprising a plurality of insulating layers and a plurality of circuit conductor layers, said insulating layers and said circuit conductor layers being laminated and bonded alternately, said insulating layers being obtained by impregnating a fibrous cloth with a varnish containing a solvent and a thermosetting resin composition comprising a poly(p-hydroxystyrene) derivative resin represented by the formula: ##STR9## wherein A is an alkyl group; X is a halogen group; R is an alkylene or alkenoyl group having 2 to 4 carbon atoms; p is an integer of 1 to 4; q is zero or an integer of 1 to 3; and n is an integer of 1 to 100, a radical polymerization initiator and an epoxy modified polybutadiene represented by the formula: ##STR10## wherein Y is an epoxy resin; and m is an integer of 4 to 100, followed by removal of the solvent by drying, said insulating layer having a dielectric constant of 3.5 or less at 1 MHz, said resin composition having flame retardancy of V-O by the standard of UL 94, a glass transition temperature of 200° C. or higher, and a thermal expansion coefficient of 10 -4  /°C. or less at room temperature.